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CVE-2021-42554

27
FAUCET Score

CVE-2021-42554 is a high-severity SMM memory corruption vulnerability affecting Insyde InsydeH2O firmware kernels across multiple versions, impacting products from vendors like Insyde and Siemens. This flaw allows an attacker with high privileges to write predictable data to SMRAM, potentially escalating privileges to SMM. With a CVSS score of 8.2 (High), the vulnerability has a local attack vector and low attack complexity, leading to high impacts on confidentiality, integrity, and availability. While there is no known active exploitation or public exploit code, the vulnerability has garnered some community discussion and media coverage, indicating awareness within the cybersecurity landscape.

Impacted Technologies

VendorProductVersion(s)CPE
>= 5.0, < 5.08.42CPE matchmatch criteria
cpe:2.3:a:insyde:insydeh2o:*:*:*:*:*:*:*:*
>= 5.1, < 5.16.42CPE matchmatch criteria
cpe:2.3:a:insyde:insydeh2o:*:*:*:*:*:*:*:*
>= 5.2, < 5.26.42CPE matchmatch criteria
cpe:2.3:a:insyde:insydeh2o:*:*:*:*:*:*:*:*
>= 5.3, < 5.35.42CPE matchmatch criteria
cpe:2.3:a:insyde:insydeh2o:*:*:*:*:*:*:*:*
>= 5.4, < 5.42.51CPE matchmatch criteria
cpe:2.3:a:insyde:insydeh2o:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.2HIGH

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.5
Impact Score
6.0
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.33%
Probability of exploitation in next 30 days
EPSS Percentile
25.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0033 is in the 54th percentile among its peer group of 360 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.2 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

kb.cert.org / vuls/id/796611
cert-portal.siemens.com / productcert/pdf/ssa-306654.pdf
Third Party Advisory
security.netapp.com / advisory/ntap-20220216-0007
Third Party Advisory
insyde.com / security-pledge
Vendor Advisory
insyde.com / security-pledge/SA-2022012
Vendor Advisory